Explanation:
By Basic Proportionality Theorem, the triangles UTV and USR are similar.
Let us consider RV as x.
is the required answer, after simplifying it.
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Or if you want to prove it similar:-
In triangle UTV and USR,
Angle TUV = Angle SUR (common)
Angle UVT = Angle URS (Corresponding angles b/w parallel lines)
By AA similarity,
UTV =~ USR.
Hope it helps :)